1. Field of the Invention
This invention generally relates to acoustic imaging systems and, more particularly to acoustic microscopy.
2. Description of the Prior Art
Microscopy is the science of using the effect of large magnification to generate usable images of very small objects. In this area of technology light field microscopy develops images from the waves that are either directly transmitted or specularly reflected from the object being observed. In contrast, dark field microscopy develops images from the waves that are scattered by the object into regions outside of the path of the directly transmitted or specularly reflected waves. In dark field microscopy the fine structure of the object is imaged whereas in light field microscopy the course, overall structure is imaged.
U.S. Pat. application Ser. No. 442,782 filed on Feb. 15, 1974, now abandoned, entitled "Scanning Acoustic Microscope, " by Mr. Ross Lemons et al. discloses an acoustic microscope for scanning an object with light field imaging. The microscope focuses a high frequency acoustic plane wave with an acoustic lens and scans an object located at the focal plane of the lens. The acoustic waves modulated by the object are recollimated by a second acoustic lens and detected with a piezoelectric transducer. The detected acoustic signal is applied to an oscilloscope that provides a visual display of the acoustic light field image of the object.